Eastern Conference Semifinals Between the Celtics and the 76ers: What You Need to Know

• The Celtics and 76ers are meeting in the playoffs for the 20th time, the most postseason matchups for two opponents in NBA history. Boston holds a 12-7 advantage in 19 series and a 54-46 edge in 100 playoff games. The Celtics won the most recent meeting, a seven-game victory in the 2012 Eastern Conference Semifinals.

• This year marks the 50th anniversary of the classic 1968 Eastern Division Finals (the Conference Finals round) between the Celtics and 76ers. With Bill Russell serving as Boston’s player/coach against longtime rival Wilt Chamberlain and Philadelphia, the Celtics became the first team in NBA history to rally from a 3-1 deficit to win a best-of-seven series. Boston went on to defeat the Lakers in the NBA Finals for its 10th NBA title.

• Boston won the season series 3-1, including a 114-103 victory in NBA London Game 2018 on Jan. 11. In that game, the Celtics overcame a 22-point deficit. The teams haven’t met in more than two months.

• Philadelphia finished the regular season on a 16-game winning streak and defeated Miami 4-1 in the first round, giving the Sixers 20 victories in their last 21 games.

• The Celtics led the NBA in defensive rating this season and the 76ers ranked third. Boston is well stocked with long, aggressive defenders to throw at 6-10 rookie sensation Ben Simmons. In the first round, Simmons became the first rookie to average at least 18 points, 10 rebounds and nine assists in a playoff series.

• Philadelphia’s late-season acquisitions, Marco Belinelli (Italy) and Ersan Ilyasova (Turkey), have paid huge dividends. Belinelli, who won an NBA championship with San Antonio in 2014, averaged 16.6 points against the Heat in the first round. Ilyasova averaged 10.8 points and 9.2 rebounds, at first helping fill in for Joel Embiid and then complementing him after Embiid returned from injury for Game 3.

• Boston’s Jaylen Brown made a big leap in his second season, finishing second on the team in scoring and shooting nearly 40 percent from three-point range. The conventional wisdom on Brown coming out of college was that his offense would have to catch up to his defense and athleticism, but he has proved to be a quick study. Brown averaged 20.5 points in the first six games of the first round against Milwaukee before injuring his hamstring early in Game 7. He is considered doubtful for Game 1 against the 76ers.

• Celtics President Danny Ainge and 76ers President Bryan Colangelo are longtime friends who worked together with the Phoenix Suns. In one of Colangelo’s first major decisions as GM, he hired Ainge as head coach, in 1996. Last year, the two former NBA Basketball Executives of the Year pulled off a trade that sent the No. 1 pick (which became Markelle Fultz) in the 2017 NBA Draft to Philadelphia in exchange for the No. 3 pick (which became Jayson Tatum) and a future first-round pick.

• Boston finished the first round starting two rookies (Jayson Tatum and Semi Ojeleye), a second-year player (Jaylen Brown) and a third-year player (Terry Rozier) to go with 11-year veteran Al Horford. That the young players look so precocious speaks in part to Danny Ainge’s personnel evaluation and Brad Stevens’ coaching.

• Boston’s Marcus Morris is a Philadelphia native. In addition to his production on the court, Morris has mentored rookie Jayson Tatum and become an emotional leader in his first season with the Celtics.

• JJ Redick turned heads last summer when he signed with the 76ers. With Redick coming off four straight playoff appearances with the Clippers, many assumed he would sign with a contender. As it turns out, the veteran sharpshooter did. Redick averaged a career-best 17.1 points and earned raves for his leadership.

• Sixers coach Brett Brown is a native New Englander (born in Maine) who played for Rick Pitino at Boston University. Brown spent one season as a graduate assistant at BU.

• Brett Brown coached the Celtics’ Aron Baynes with the Australian national team and was instrumental in getting the rugged big man his first NBA shot, with San Antonio, in 2013. Baynes started 67 games for the Celtics during the regular season. He’ll play a key role in this series trying to slow down Joel Embiid.